Month: September 2017

Recumbent trike – idlers and longer ride

The trike is now mostly done, but the drive train was giving me grief. The idlers were not working out and I replace the rear cassette due to skipping.  The previous owner of the components had beat the bike more than I initially thought with damage to the cassette and outer crank chain ring , both of which had to be replaced.  Maybe there was a good reason he cracked his Trek carbon fiber frame?

After having problems with:

  • Metal pulleys as idlers . These were garden tractor style A size v-belt pulleys form Northern Tools. There were metal shavings everywhere and the chain would pop off.
  • Hybrid pulleys. I used sprockets from the old gear cluster and 3D printed nylon sides and spacer to center them over the ball bearings. They held together, but after 5 miles were wobbling badly and the low gears were skipping. The chain would rock off the sprockets, ride on the sides or pop off all together. The nylon withstood a huge amount of force and merely deformed without breaking. However with a 9/32″ wide bearing, there was too much lateral force.
  • Hybrid pulleys versions 2&3. I used PLA for the test models. However, it blew apart under stress in less than 3 miles.  There were problems with geometry and the bearing to sprocket interface.   I was not thrilled with the thought of making new parts out of aluminum to withstand the stress and support 2 bearings per pulley. Nylon flexed too much and I would have needed to bake the spool again due to the humidity. to drive off the absorbed moisture prior to printing.

I then again turned to Google. This lead to Terra Cycle idler pulleys. http://t-cycle.com/idlers-chain-management-c-41/idlers-c-41_9/sport-power-idler-p-134.html They were highly recommended on the AZ website and elsewhere.   I ordered a couple of these and one of thier 28″ chain tubes as an upgrade from the garden hose.  With the research, I also decided to redo the chain tube supports and let the sprockets and chain tube slide freely on the shaft rather than being held side to side in a fixed location.   The resulting setup is seen below.  I used 1/16″ x 3/4″ aluminum stock and bent it to match the chain tube. This was easier to make and the integral chain retention is a huge benefit.

You can also see above, that when the old front idler shattered, the chain was then rubbing on the underside of the handlebars.

With these installed, I dressed for cycling (cycle shorts, not my regular cargo shorts) so as not to appear to be flashing the passersby. The padding of the cycling shorts was not necessary but the snug fit was.  I then did an intermediate length “shake down” ride. Just shy of 20 miles and nothing fell off or bound up. I still need to do some derailleur adjustment (some skipping under hard stress) and front brake fiddling (some squeaking/ rubbing of he disks) and front wheel toe-in adjustment as well as tying down the right front brake cable which is rubbing my calf.

However, it rode very well overall. It was comfortable and fun. There were plenty of interested looks on the bike trail, as you might expect.  Max speed was 26 MPH and average was 12.  Still below my road bike, but I hope with a bit more tuning and remembering to top off the tires, I should break even.  My back, wrists and hands felt much better than on the road bike. Conversely, my shoulders and biceps were a bit stretched as my hands are below and behind my back due to the reach for the handlebars. Legs were pretty good, but my shins are a bit sore tonight.  I expect that there will be some “human break in” for the new riding position.

 

Recumbent trike – Paint

So now I have striped the trike back down to the frame. There was more touch up welding and grinding going on. The Atomic Zombie website motto seems to be “weld, cuss, grind, repeat” and it fit my welding skill level. So after things got close, I fixed any questionable spots that appeared and finished at 80 grit with a flap disk. Then I got out the Bondo to fill the last gaps, divots and make the fillets pretty. This took a few coats not counting the one where I mixed in spot putty rather than hardener  (same size tubes and color – darn). So I also had to clean off the non-curing mix with lots of acetone and paper towels. Then after recoating with a proper mix, it was more sanding filing and then priming. The fillets all look nice now and errant grinder marks have disappeared.

For the paint,  I used Rustoleum self-etching primer and the color coats were Rustoleum Professional High Visibility Yellow.  While a 2 part auto paint or powder coating would be more durable, this paint combination has served me very well on multiple machine tool builds and rebuilds (14″ Radial arm saw, Southbend 13″ lathe, Bridgeport Mill and the CNC router).  Undercarriage parts were painted Gloss black for contrast. Unfortunately a week later it is still rather soft and scratching during assembly.

This paint has a less <1 & >48 hour recoat window. I can generally push this to < 3 hours but at 12-18 you will definitely get blistering much of the time. So the painting was done on a weekend where I had a full day available for prep, prime and paint.

I had some business travel scheduled so this forced a week to allow the paint to harden fully. Plus I was getting started on the new idler pulley design. The original pulleys from Northern tool are a bit narrow and wearing badly.   So I will make some similar to what you can buy from TerraCycle for a fraction of the cost using spare gears and 3D printed parts.

Recumbent Trike – Steering pull solved

The steering pulling to the right bothered me.  The 1.5 to 2 degree difference in the caster angles was there and it had to be the clue I needed. However, the angle readings were varying on each try but overall the right wheel had less caster than the left. I really did not want to cut off the arm and realign the whole thing again as that was not easy the first time. Searching at lunch for caster steering problems, I came across a Quora post that said if the caster is uneven the car will pull towards the side with less caster. https://www.quora.com/How-caster-angle-affects-to-the-vehicle-dynamics. This was the answer I needed!

So, I decided to cut the front tube perpendicular to the long axis. This would give me the ability to adjust the caster without messing up the camber.  WIth a 2 degree angle error and 1.5″ tubing I would need to have a slot 0.078″ or just over 1/16″ . One slice with a cut-off blade in the angle grinder would be about right.  I placed a straight edge against the back of the spindle tubes and marked across the arm.

Measuring the angle exactly is very hard. So I enlisted my wife’s help and used a pair of 2 foot long winding sticks placed against the front edges of the steering bearing cups. Sighting along these from the side I could see the angles were plainly different.  Winding sticks are used in woodworking when flattening benches, aligning jointer beds and other areas where you are looking remove twist in a surface.  Below, I am holding a ruler in the position where each of the winding sticks was placed. 

After slicing through the top and then the sides, a bit of downward pressure closed the gap.  A quick check with the winding sticks again showed that they were now almost exactly parallel – the difference was gone! Now it was time for a couple of hot tack welds and a test ride. You can see the gap at the bottom, where the cut is folded and that it is tight at the top.

This did the trick. I can now go 100-200 feet hands free with very little drift. I will still tighten up the steering a bit to add some friction as bumps will cause a deviation (yes more caster would probably help but I am going to leave this one alone now.  So it was now time to weld over the length of the joint and start to grind flush. It gets dark early now so I was not able to completely finish and it will be easier when the bike is disassembled for painting.

Now I need to figure out the rear chain skipping…

Recumbent trike front end work and test rides

The front derailleur needs a tube on which to mount. This ended up being a piece of water pipe that was bored out to a reasonable wall thickness. The pipe was then tacked in place on the bottom bracket as the derailleur range of motion was tested prior to final welding.

The used front derailleur is a top pull design. So in order to not have an excessively long mounting tube a special bracket was made to support the cable end.  It is made from a piece of steel flat stock and a cable end braze on piece.  The braze on piece was brazed into the bracket and the whole thing welded on with some intermediate test fitting.  

Afterwards, I flipped the trike back up on the buckets for more work. However it was a bit too soon and I am a bit too clumsy, so the bracket branded my left arm. This is what it looks like a day later.

You can also see one of the sets of water bottle mounts in the photo of the crank assembly. These were more braze on bits. They require a 1/4″ hole in the tubing and are an M5 thread.

The next pieces were a rear mount for the tail light and adding the parking brake. The parking brake, seen below, was a down tube mount gear shifter in its previous life on my dad’s old bike. It was trimmed down and brazed onto the frame under the seat. It still needs a dip in rust remover and a new cable but it works.

So here is the nearly finished trike. Ready for test rides, body work (more grinding and some filler) and painting.

Ready for the next test ride (minus helmet). One water bottle mount (stolen from my road bike) in place.

There is still tuning required. The front derailleur does not like to shift onto the lowest gear and the rear skips when I pedal hard. I don’t know if it is an adjustment issue or that the used gear cluster is too worn. With the recumbent,  there can be a lot more torque applied than when upright.  I can make it up the driveway, but the speed is limited by rear gear skipping (darn).

The top speed riding around our neighborhood so far is 23 mph. Not great, but not horrible either. The trike tends to pull a little to the right when hands free. I will probably add a tiny bit of friction in the steering linkage somewhere to account for this. I really don’t want to cut off the right front wheel arm and tilt it a few more degrees to add more caster. I see 9 degrees forward on the right vs the 10.5 on the left as best I can measure.

Now it is time to tear it down, cut down the front rail tube, do some body work and paint it. There are also some parts to 3D print, including new chain idlers. The Northern Tool idler pulleys are too narrow and generating lots of metal shavings on the chain and I am sure excess friction as well.

Smoked pork loin chops

Today, Teal wanted pork chops and I had a craving for smoked pork chops. However the smoked pork chops at the store did not look all that appealing. However, thick cut boneless pork loin chops were on special.  So a compromise was in order, and it was still early enough in the day to get these done. So here is the experiment:

2 very thick cut pork loin chops, about 1.5 lbs. total.   These were a good 1.5 ” thick or more.

Brining

  • 2/3 c brown sugar
  • 2 Tablespoons kosher salt
  • 1.5 tsp Penzey’s jerk pork spice    You could use McCormick or others but they vary a lot in flavor, like curries do.
  • ~2 c water

Mix the brine.  Trim the chops removing the fat and sliverskin on the outside.   Poke with a paring knife repeatedly all the way through. This helps the brine to get absorbed more evenly.   Soak in the brine covered in the fridge for 4 hours or so.

Smoking

Prepare the smoker. I am using Big Green Egg. Start the charcoal with wood sticks for kindling. The “starter blocks” take too long to burn off and get rid of the paraffin odor. I added some nice big chunks (3-4 across) of cherry for flavor. Once the fire is going, set up for indirect cooking with the platesetter under the grate and set the Heatermeter to 225 degrees.   Smoke for 4 hours.

The chops hit 135 degrees internal temp at 1.5 to 2 hours, so anything in the 140-145 range at the end will be plenty safe to eat.  If in doubt, refer to Doug Baldwin’s pasteurization tables (the temps are for a sous vide water bath and therefore overkill here where I am watching the internal temps).  http://www.douglasbaldwin.com/sous-vide.html#Table_5.1.

Results

The smoking temp overshot a bit at first, to 245-250 for the first 45 min as I neglected to put the daisy wheel damper on the BGE.  I was to anxious to get the trike out for a test ride.  From 1 hour on, it was staying right at 225. We pulled the meat at 3.5 hours rather than the planned 4 due to the aroma of not only the pork but also of the apple crisp that Teal baked for dessert. Our apple trees are providing a nice crop this year.

When cut, the smoke ring penetrated 1/3 of the way in from the edges (nice!). This is fairly “light” smoke. The pork was juicy, fork tender and delicious. This experimental recipe is a keeper.  In the future, I plan to run more time and temp variations.

Recumbent Trike cabling

Hmmm, One brake lever and two front brakes.  This needs a bit of work. I considered the dual brake line brake levers, but they don’t look exceptionally well made. I also considered dual hydraulic brakes, but I would still be stuck with the original piston in the grip and reduced braking power. Using caliper brakes linked together was rejected mostly due to structural issues (long support arm for the brake). This left taking good mechanical disk brakes and linking them together. So, I settled on a new set of Avid BB-7s and 160mm rotors.

Looking over photos from the web I saw a variety of ways of linking up the brakes that were either needed some aesthetic help (big assembly on the handlebar),  were mechanically unsound ( lever system with then unequal pull on the 2 brakes) or overly bulky. So I settled on a system where I would use an aluminum block to attach the 4 brake cables : two to the brakes, one to the handlebar and one reserved for the yet uncompleted parking brake.  In the photo below you can see the bottom section of the block. It is made form 3/4 x 1/4″ aluminum stock. The holes for the brake cables on the left are drilled 7mm in diameter and he grooves were cut with a slitting saw, although the band saw or hacksaw would have worked as well. You can see that the exits are a bit too close together. I made the bracket before the adjusters arrived and the closest they can be set is about 12mm / 1/2″ on center. So the holes and slots should be a bit further apart to minimize friction on the cable entry to the adjusters.

Here is the view from underneath the frame. The “combiner block” assembly is really not visible from above.

Now it was time to add the cover plate. This serves 2 functions: retaint the outbound brake cables and clamp the inbound ones from the handlebar and future parking brake. You may ask how it retains the outbound cables? This is due to the slots not being cut all of the way through. The “dumbells” on the ends of the cable drop into the, holes after a bit of filing, but are prevented from falling through by the slots for the cable only being about 2/3 of the way through the block.

Next was getting the brake line sleeves properly run and not rubbing on anything.


I had to turn down the heads of the screws to get the 2 to fit next to each other. You do need all 3 for clamping pressure.

The long bolts for the chain idlers were trimmed off and the spot welds made firm.

After this the chain was run and the inelegant but practical garden hose return run was mounted. The chain run actually takes nearly 3 full chain lengths to cover the distance. I used SRAM PC971 chains for this (at $20 a pop)!  I mounted the chain and set the length per the Sheldon Brown recommendations. The front derailleur is not yet mounted, so I will need to see if I truly have enough take up for the lower gears. However at this point I should only need to shorten the chain rather than lengthen it and I was using a used chain for the 3rd one, so if it ends up looking like confetti, so be it.

With steering, brakes and propulsion hooked up it was time for some test drives. I double checked the brakes and steering connections and was ready to set off down the driveway (which is steep) and for a cruise around the neighborhood.

The shifting was not perfect and I nearly got hung up in high gear – yes I should have set the derailleur end stops. I was riding around the neighborhood at a nice clip, looking ahead and I became thankful that I was wearing underwear otherwise the neighbors would have had quite a  show with my shorts billowing upwards in the breeze (not a problem on a regular bike). The handlebars were not quite tight and I got them set to a comfortable.   On the way back, I was dismayed that the pedal resistance was higher than expected.  I then stopped at the bottom of the driveway and pushed the trike up – remember I have no low gears without a front derailleur and on my road bike I am normally in gear 1-3 on the way up.

At the top I tighten the handlebars and notice the front wheel hub nuts are loose. No wonder the resistance increased and thankfully it must be pretty hard to lose a front wheel with disk brakes.  So I tightened the hub nuts and added the jam nuts.  I also fiddled with the toe in of the front wheels to minimize the steering twitchiness I had been feeling.  Now it was time for another test.   This time speeds were up and steering settled out.

Now it was time for the kids to come over for Labor Day dinner and I had prepared another big batch of smoked chicken.

After dinner it was my son David’s turn to try the trike. He took it on the same route, and came back with a big smile and started up the driveway (remember I said it has no low gears). He gave it a valiant effort and made it half way up.  Now he was stuck. Cnt go forward, and really can’t get off either, for as soon as he lets go of the brake to swing his body up forward to get off, the trike slides back down the driveway (hence the need for the yet unfinished parking brake).   So rather than risk having a father-less grand-daughter, I go to rescue him and prop my leg behind the trike while he gets off .

All in all, it is a success so far, but there is still more work and fine tuning to go.